[en] Neutron yields from (α, n) reaction and spontaneous fission, which are very important in analyzing radiation shielding of spent fuel storage, transport, and safe handling, were collected and evaluated to determine the recommendable values. For thick target neutron yields from (α, n) reactions, the most accurate data of West and Sherwood, the newest evaluated data of Heaton et al., and the data of high atomic number nuclides evaluated by Nakasima were adopted. And the experimental data at a high energy region of Stelson and McGowan were also used as references. The data for estimating neutron yields of unmeasured elements are also prepared in this Data Book by using theoretical values of (α, n) excitation function and the evaluation formulas on stopping power by Ziegler. For neutron yields from spontaneous fission, the values recommended by S. Raman were mainly adopted. Neutron energy spectra of (α, n) reaction and spontaneous fission were also included in this Data Book. Neutron production data of compounds can be obtained by using the neutron yield and stopping power of each single element. (author)